Low-density high-plastic nial reinforced ultra-high-strength steel and its preparation method

Abstract

The invention relates to a low-density high-plasticity NiAl-reinforced ultrahigh-strength steel and a preparation method thereof, belonging to the technical field of alloy steel. The alloy comprises the following components in percentage by weight: 0.5-1.5% of C, 10-30% of Mn, 5-12% of Al, 5-15% of Ni, 0-5% of Cr, 0-0.2% of Nb, and the balance of Fe and other inevitable impurity elements and minor elements, such as Si, Ti and the like. The preparation method adopts a vacuum induction+vacuum consumable remelting or electroslag remelting technique. Compared with the prior art, the low-density high-plasticity NiAl-reinforced ultrahigh-strength steel has the advantages of favorable comprehensive properties, low density, high plasticity, ultrahigh strength and the like. The density is up to 6.5-7.2 g / cm<3>, the tensile strength is up to 1350 MPa above, and the elongation percentage is up to 10% above.

Description

technical field [0001] The invention belongs to the field of alloy steel, and in particular relates to a low-density high-plastic NiAl reinforced ultra-high-strength steel DT550 and a preparation method thereof. The steel has excellent properties such as low-density high plasticity and ultra-high strength, and the density reaches 6.5-7.2g / cm 3 , The tensile strength reaches above 1350MPa, and the elongation reaches above 10%. The bar size reaches φ200mm or more. Background technique [0002] Ultra-high-strength steel has always been an indispensable material for the key load-bearing structures of aerospace. Reducing the density and increasing the strength-to-weight ratio have great significance for the development of steel for aviation and aerospace structural parts. According to relevant information, for a supersonic aircraft, if other conditions remain unchanged, if the empty weight of the aircraft increases by 1%, the commercial load of the aircraft will decrease by 2% t...

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Problems solved by technology

Since the main strengthening method of Fe-Mn-Al-C low-density steel is kapa-carbide precipitation strengthening, the improvement of kapa-carbide precipitation strengthening depends on the content of Al and C in the steel, but studies have shown that with the addition of Al, With the increase of C element composition ratio and content, к-carbide and some other carbide phases will appear in the structure, and even B2 (FeAl) and DO will appear. 3 (Fe 3 The second phase of intermetallic compounds represented by Al) may be in the form of ferrite, austenite or dual-phase matrix, which seriously deteriorates the plasticity of steel. Therefore, the traditional Fe-Mn-Al-C quaternary system The limit of Al content in low-density steel is 12%, and the limit of C content is 1.5-1.7%. In order to further increase the strength, it can only be strengthened by deformation. At the same time, it is imperative to increase the size of the parts and develop a new strengthening method that does not rely on rolling

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